Tank drained from a tank problem.

I'm not sure how to start this problem. Can someone help me with this.
A large tank with capacity of 600L initially contains 200L of pure water. Brine with a salt concentration of 4g/L is pumped into the tank at a constant rate of 15L/min. The solution in the tank is well mixed at all times, and is drained from the tank at a rate of 10L/min. How much salt is in the tank at the moment the amount of brine in the tank reaches capacity?